Branch line deployment mechanism

ABSTRACT

This invention relates to the deployment of branch lines used in longline fishing. A branch line deployment mechanism is provided which comprises deployment means for casting a baited branch line and drive means associated therewith. The deployment means comprises an arm connected at one end to the drive means, having at its other end means associated therewith to accommodate a baited line, such that the arm is capable of rotation about said connected end. The rotation is imparted to the arm intermittently by the drive means so as to provide a first or loading period in which the arm may be loaded with a baited line and a second or throwing period in which the arm casts the baited line.

FIELD OF THE INVENTION

This invention relates to the deployment of branch lines used in theso-called longline fishing industry. In particular, it relates tomechanical means to deploy branch lines with bait attached from afishing vessel.

Whilst the invention may be equally well suited to a variety of otherfishing methods and even locations, for convenience, the followingdescription refers to the use of the inventive device in longlinefishing. Any reference however to the use of the invention in suchlongline fishing is meant to encompass any form of fishing, where bysuitable adaptation, the invention may be so used. Similarly, the deviceof the invention lends itself to the casting of other materials orsubstances besides bait, with or without lines attached and accordinglyit must be understood that the invention is not limited solely tolongline fishing or even to fishing in general.

PRIOR ART

The longline fishing technique is specifically utilised for tunafishing. In this method, for example, each ship deploys up to 3,000branch or tracer lines, each with baited hooks. The ship travels for sayfive hours at approximately 20 kph, feeding out the so-called longline(main line) which extends up to 100 kilometers. Each branch line isspaced approximately 33 meters apart, along the main line. Thus, abranch line is baited, attached to the main line and cast approximatelyat six second intervals. In other words, a branch line is cast everyfour to ten seconds for approximately five hours before the ship turnsaround, to retrace its path and bring in the main line and hopefully theday's catch.

A team of four or five people performs the function of casting thebranch lines, which is necessarily labour intensive. One person selectsthe branch line, a second baits the line, a third deploys the linewhilst a fourth clips the line onto the main line, which is fed into thesea from the rear of the ship.

Although the length of each branch line is 40 to 70 meters, it is onlynecessary to cast the line beyond the wake or turbulence of the ship.Thus, a minimum throw of some 12 to 15 meters is required. The baittypically weighs 100-300 grams.

The branch lines are cast from the stern of the ship on the port (left)side only. Casting to the port side results from right-handed throwingfrom a person standing at the stern of the ship. This manual deploymentof branch lines contributes to significant reductions in fishingefficiency. Port side only branch line deployment, particularly whenthrowing into the wind, causes many of the baited branch lines toencounter the turbulence of the boat rather than be cast beyond it.

Since the bait does not sink quickly in these circumstances, it allowssea birds access to the baited hooks which, it is estimated, costs theJapanese fishing industry in southern waters alone a minimum of A$7million annually in lost fishing effort. Sea birds, particularlyalbatrosses, also get caught on the baited hooks. This is itselfbecoming a serious conservation issue that could potentially threatenthe fishing industry. Furthermore, gear damage and loss is also highwhen manual deployment is thus necessarily confined to the port side,only to be aggravated by the effects of strong winds and sea turbulenceresulting in fouled lines, including their entanglement with propellers.

The present invention has therefore been conceived out of the need tomechanise branch line deployment in order to significantly reduce lossof bait to birds, minimise the mortality rate of sea birds includingalbatrosses, and reduce gear damage and loss. In addition, mechanisationwould allow larger, more fuel efficient propellers to be utilised sinceat present, ships' operations have been compromised in order to reducegear damage and bait loss arising from manual port side deployment ofbranch lines.

It will be readily appreciated that operating efficiency is vital inthis industry where there is limited access to the resource beingfished. Furthermore, the variability in deployment efficiency byindividual crew members, contributing significantly to the problemsnoted above, would be largely overcome through mechanisation. At thevery least, the present invention provides an alternative to previouslyproposed systems.

DISCLOSURE OF THE INVENTION

According to the present invention there is provided a branch linedeployment mechanism for use in longline fishing comprising deploymentmeans for casting a baited branch line and drive means associatedtherewith, wherein the deployment means comprises an arm connected atone end to the drive means, having at its other end means associatedtherewith to accommodate a baited line, such that the arm is capable ofrotation about said connected end, rotation being imparted to the armintermittently by the drive means so as to provide a first or loadingperiod in which the arm may be loaded with a baited line and a second orthrowing period in which the arm casts the baited line. Means to rotatethe arm in either direction, that is, clockwise or counter-clockwise, ispreferably provided in the mechanism.

Preferably during the first or loading period the arm remainsessentially stationary to facilitate loading.

In order to accommodate the baited line, the arm, at least in the regionassociated with its outer free end, may be of generally U-shapedcross-section thereby providing a channel or recess along its axis tohold the baited line prior to casting it. Alternatively, the arm may berelatively flat in cross-section, having the appearance of a paddle,with a blade approximately perpendicular to a support plate mounted tocooperate with the arm, so that in use the baited line can be placed onthe plate, the arm being caused to sweep over the surface of the plateas it is rotated in order to cast the line. Naturally the plate may alsobe provided as an optional facility even where the U-shaped channel isutilised, in order to catch misplaced bait etc.

With advantage the axis of rotation of the arm is provided at an angleto the vertical, for example between 5° and 20° to the vertical, so asto provide sufficient lift to ensure the baited line is cast anappropriate distance. Furthermore, it is preferred that the arm itselfalso be angled between 5° and 20° with respect to the planeperpendicular to the axis of rotation. If the unit and the arm are thusequally angled as indicated, then the arm will in one sector of itsrotation be substantially horizontal, hence providing a convenientposition for loading, whilst elsewhere in its travel about the axis willprovide an upward sweeping motion to facilitate casting.

Preferably the deployment mechanism is provided with attachment means(for example a bracket) for attaching it to a fishing vessel and morepreferably externally thereof. The deployment mechanism is alsopreferably provided with a gimbling arrangement of known meansassociated with said attachment means to facilitate keeping themechanism level despite the roll of the ship.

When the mechanism is thus situated or mounted external of the ship,with the axis of rotation angled towards the ship and with an equallyangled arm as discussed above, such that the then horizontal loadingposition is adjacent the stern, loading is further facilitated and thethrowing action then conveniently simulates manual throwing. Howeverthis mechanical throwing is of course achieved with greater precision,control and effective distance when compared to manual throwing.Additionally, where the rotation of the arm may be effected in eitherdirection, it may be made to do so depending on the prevailing weatherconditions, thus causing the bait to be cast to the port or starboardside as required, by means of suitable reversal of the drive means.

The drive means for the mechanism may be any suitable drive capable ofimparting sufficient rotational velocity to the deployment arm so as tocast or throw the baited line beyond the turbulence of a fishing vesselon which it is used. Furthermore it is required that the drive to thearm be capable of interruption so as to provide a period for loading itwith the baited line.

The throwing action may be achieved for example by simply acceleratingthe arm and bringing it to a sudden halt thus causing the baited line tocontinue by virtue of its momentum. This arrangement also provides aloading period whilst the arm is held stationary prior to releasing itfor the next throw. Alternatively, the throwing action may be achievedby rotating the arm within a guide mechanism provided with an opening inthe form of a gate or aperture or the like, such that when the armpasses the opening, the baited line is caused to be flung therefrom.Even without a guide, if sufficient angular velocity is achieved, athreshold will be passed and the baited line will of itself be thrownclear of the arm. In either of these latter situations however, the armwould still need to be brought to rest or decelerated to allowsubsequent reloading.

The arm is conveniently and automatically locked in its stationaryloading position, for example, by means of a cam follower, which iscaused to engage with a cam on a shaft which supports the arm and aboutwhich the arm rotates. Release of the cam follower and hence the arm isachieved by activating a release mechanism therefor, preferably ahydraulic release mechanism.

Alternatively, engagement may be achieved by means of a hydraulicrelease ram acting in cooperation with a peg or lug located on asuitable position about the periphery of the drive shaft, for example ona plate affixed about the shaft which supports the arm.

Referring to the drive means, one suitable drive mechanism for exampleis provided by a conventional motor which cooperates with a tensioningspring associated with the arm, so that in use, the arm is locked orheld in position by suitable means such as those described above, thuscausing the motor to operate against the spring thereby tensioning ituntil the motor reaches its stall position, whereupon the spring may bereleased causing the arm itself to accelerate and cast the bait asdescribed above. When the arm is brought to rest, for example by using acam follower acting against a cam to act as a lock or by using a ramacting directly on a suitable lug, the spring will again be wound up bythe action of the motor thereon. Bait may then be loaded and theoperation repeated.

Whilst the aforementioned motor/spring arrangement does allow reversalof the direction of rotation, this may not be especially convenientsince, in general, reversal will be best achieved by not only reversingthe motor (usually relatively easy), but also by replacing the springwith one of appropriate opposite hand. Otherwise the spring will beplaced in extension rather than compression and is more likely to fail.

Alternatively, with advantage, the drive means may be provided by ahydraulic motor which drives the arm either directly in conjunction witha hydraulic accumulator or via a clutch mechanism. In the firstsituation, if the arm were unimpeded, it would rotate freely with themotor. However if it is engaged, for example by means of a cam followercooperating with a cam to lock it in one position or by means of ahydraulic ram and lug arrangement, then the hydraulic motor builds uppressure, and the pressure is stored in a hydraulic accumulator(comprising for example a piston) by known means. By releasing the camfollower or hydraulic ram as required, the arm is released ordisengaged, and there is provided an immediate acceleration to the armfacilitated not only by the pressure in the motor itself but assisted bythe pressure built up in the accumulator.

In the second situation, where a clutch is provided, and engagement ofthe arm is effected as described above (is locking the arm in theloading position), the clutch is triggered at the same time as therelease mechanism is activated, thereby causing the arm which is nowotherwise free to rotate, to be thus rotated with the motor.

By analogy with the previous embodiment using a motor/springarrangement, the hydraulic accumulator or clutch arrangement substitutesfor the spring arrangement. In these latter embodiments however it willbe readily appreciated that reversal of the direction of rotation of thearm is more readily and simply achieved by reversing only the hydraulicmotor.

Thus by using the hydraulic motor, for approximately one half of asingle rotation following its release, the arm is caused to accelerateby the rotational force exerted by the motor, whilst for the remaininghalf it rotates freely with the motor in equilibrium until it is madestationary by engagement of the cam follower in the appropriately shapedcam or engagement of the hydraulic ram with a suitable lug. Either thepressure thus experienced in the motor is stored as described above inan accumulator or a clutch allows the motor to rotate freely. In eithercase, the motion exhibited by this action is in fact quite smooth and isconsiderably less violent than the use of the conventional motor/springmechanism discussed above.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described by way ofillustration only with reference to the drawings, in which:

FIG. 1 shows an embodiment of a branch line deployment mechanismaccording to the invention in side elevation,

FIG. 2 is a detail of an arm suitable for use in the embodiment asillustrated in FIG. 1, and

FIG. 3 is a detail of a hydraulic release mechanism for actuating themechanism based on a ram acting directly on a suitable lug.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE PRESENT INVENTION ANDBEST MODES OF CARRYING OUT THE INVENTION

Referring to FIG. 1 there is shown a branch line deployment mechanismgenerally referenced 11 comprising a hydraulic motor 12 and a deploymentarm 13.

The device 11 is attached to the stern of a ship 14 by means of agimbling system 15 (with counter weight 20) of known type via bracket16. The gimbling system 15 provides for level operation of thedeployment mechanism 11 despite roll of the ship. Extending rearwardlyfrom the gimbling mechanism 15 is support arm 17 to which is attachedthe hydraulic release mechanism generally referenced 42. The hydraulicmotor 12 is mounted on the underside of support arm 17. Hydraulicallyconnected to motor 12 by means of directional valve 24 is a hydraulicaccumulator 25. The motor 12 provides direct drive to the arm 13 viacollar 19 which is mounted on the drive shaft 21 of the motor 12. Anexample of a suitable U-shaped arm 13 is shown in FIG. 2.

FIG. 3 shows in detail the release mechanism 42 and associated plate 23,which is mounted on drive shaft 21. Plate 23 incorporates a pin or lug39 which is held against a ram 40 in order to lock plate 23 at one pointof its rotation. Ram 40 with its associated hydraulic cylinder 42 ispivoted about axis 41 and is itself restrained from lateral movement bymeans of stops 43 and 44. Although hydraulic ram 40/42 need not bepivoted, it has been found useful to do so to facilitate stopping theplate 23 and hence arm 13, at the same position (i.e. relative to thestern of the ship) in order to load at the same location irrespective ofwhether port or starboard deployment is utilised. If ram 40/42 were notpivoted, lug 39 would be caused to stop either side of the ram 40,effectively shifting the loading position.

Thus in use, actuation of the hydraulic release cylinder 42 allowsdisengagement of the ram 40 (through withdrawal or retraction thereof)from the lug 39, with the consequent rotation of arm 13 (which is drivenby motor 12). Upon one rotation thereof, ram 40 will again engage withlug 39 by virtue of ram 40 being allowed to resume its normal or lockingposition.

Therefore, utilising the above described release mechanism, thedeployment mechanism 11 allows for the loading of the deployment arm 13in the locked position when the arm 13 is conveniently adjacent thestern 14 of the ship. The hydraulic release mechanism 42 may be actuatedto allow rotation of the arm 13 thereby causing the baited line to becast. After one rotation of the arm 13 it is again locked in position bymeans of the ram 40 as described above. The drive motor 12 continues tobe supplied with oil thereby building up pressure therein, the overflowof which is accommodated in the hydraulic accumulator 25. After loadingarm 13 with the baited line, the release mechanism 42 may be againactuated causing the arm 13 to be once again rotated by means of thepressure exerted by the driving motor 12 and hydraulic accumulator 25.

Although it is usually required that loading be achieved every sixseconds, corresponding to the normal interval between each deployedbranch line, it has been found that this equipment allows the reloadtime to be less than two seconds. Furthermore, reverse directiondeployment to either the port or starboard side may be achieved withinthree seconds which allows the line setting process to continueuninterrupted despite changing direction. Mounting of the deploymentmechanism to the ship by means of the gimbling arrangement allowscompensation for roll, so branch line deployment direction and distanceremain largely unaffected, irrespective of the sea conditions.

A finger touch manual firing mechanism (not illustrated) associated withthe hydraulic release mechanism may be provided for efficient operationof the deployment mechanism so that line setting routines can bemaintained.

The branch line deployment distance may be conveniently varied to auseful maximum of about twenty meters. Whilst the machine is capable ofthrowing for some fifteen to twenty-four meters, it is preferred tothrow in the range of fifteen to eighteen meters. The distance of throwis reduced by restricting the flow of oil from the accumulator 25 to themotor 12.

Deployment direction may be conveniently set at any appropriate angle tothe axis of the ship, although a deployment direction of 10° has beenfound to be suitable. With advantage, the equipment may be constructedfrom stainless steel for durability. Safety is enhanced since movingparts are outside the work area and may be shielded effectively fromsame. The straightforward design and the relatively few movingcomponents permit for the efficient replacement of parts and maintenanceof equipment. The equipment may be installed relatively quickly and iscompatible with existing power sources.

From the foregoing, it will be readily apparent that numerousmodifications and variations can be effected without departing from thetrue spirit and scope of the present invention. It will be understoodthat no limitation with respect to the specific embodiment illustratedherein is intended or should be inferred.

I claim:
 1. A deployment mechanism for use in deploying a branch line inlong line fishing, said deployment mechanism including:a drive motorhaving a drive shaft; an elongate deployment arm having a free end, andan opposite end connected to said drive shaft of said motor, forrotational movement of said free end of said deployment arm about alongitudinal axis of said drive shaft; an axially extending channelbeing provided at the free end of said deployment arm for holding abaited line; and drive means for imparting an intermittent rotationalmoment to said deployment arm; whereby in a first mode said deploymentarm is held to allow for the loading of a baited line into said channeland in a second mode said drive means imparts a rotational moment tosaid deployment arm, so as to cast said baited line out of said channeland away from said deployment arm.
 2. A branch line deployment mechanismas claimed in claim 1, wherein the drive means rotates the armhorizontally.
 3. A branch line deployment mechanism as claimed in claim1, wherein the drive means is capable of rotating in a clockwisedirection or counter-clockwise direction.
 4. A branch line deploymentmechanism as claimed in claim 1, wherein the action of casting thebaited line is achieved by accelerating the arm.
 5. A branch linedeployment mechanism as claimed in claim 1, wherein during the firstmode or loading period, the arm remains essentially stationary tofacilitate loading.
 6. A branch line deployment mechanism as claimed inclaim 1, wherein the drive means is a hydraulic motor.
 7. A branch linedeployment mechanism as claimed in claim 1, wherein the arm is engagedautomatically in a stationary loading position and can be releasedtherefrom by means of a hydraulic release ram acting in cooperation witha peg or lug located about the periphery of a drive shaft which supportsthe arm.
 8. A branch line deployment mechanism as claimed in claim 1,wherein the channel is of a generally U-shaped cross-section extendingalong the axis of said arm.
 9. A branch line deployment mechanism asclaimed in claim 1, wherein the axis of rotation of said arm is providedat an angle to the vertical.
 10. A branch line deployment mechanism asclaimed in claim 1, wherein the arm is angled with respect to a planeperpendicular to the axis of rotation.
 11. A branch line deploymentmechanism as claimed in claim 1, wherein means are provided forattaching said mechanism to a fishing vessel.
 12. A branch linedeployment mechanism as claimed in claim 1, wherein the deploymentmechanism is provided with gimbaling arrangement to facilitate keepingthe deployment mechanism level despite any rolling of a ship.